The field of the invention relates to filters for aquariums. In particular, the field relates to sock filters for aquariums.
Filter apparatuses for aquariums are known in the art. For example, filter apparatuses are described in U.S. Pat. Nos. 5,246,517; 5,087,357; 4,622,148; and D353,649; the contents of which are incorporated herein by reference in their entireties. “Sock filters,” also known as “bag filters,” are utilized in aquarium filter apparatuses for receiving water from an aquarium tank and filtering debris. Sock filters commonly are composed of a filter material that permits water flow therethrough while retaining debris. Through extended use, as the filter material becomes clogged, water no longer flows through the sock filter. The clogged filter material retains aquarium water received from the aquarium tank and the sock filter fills with water. In vertical sock filters, aquarium water with unfiltered debris then flows over the top of the sock filter and unfiltered debris is returned to the aquarium tank. It is desirable to provide a sock filter comprising multiple graded filter material in order to prevent or delay overflow of aquarium water over the top of a clogged sock filter.
Sock filters commonly have a collar attached to the filter material. The collar is inserted into an opening in a filter apparatus such that the filter material extends vertically below the opening. It is desirable to provide a sock filter that has a collar for securing the sock filter in the filter apparatus and for orienting the sock filter in the filter apparatus.